An experimental study of the adsorption process of carbon and nitrogen oxides was carried out at various flue gas flow rates and concentrations of harmful components. The optimal conditions for the adsorption process were determined at various flue gas flow rates. It has been demonstrated that the efficiency of adsorption of carbon and nitrogen oxides depends on the flue gas flow rate, the concentration of these components and the process temperature. A design has been developed for an environmentally friendly nozzle for a chimney using granulated blast furnace slag as an adsorbent, which allows achieving a degree of gas purification of 50–55% or higher under optimal operating conditions.